Stuttering during scrubbing in FCP

I'm having issues with three FCP at work. There seem to be a stuttering issue when scrubbing through video. Other FCP stations are fine at work, it's just these three. All stations have the same settings on FCP and all MACs have the same specs. Not sure how to fixed the issue. Tried restarting the computers a few times and it still has this issue. Anyone's help will be appreciated. Thanks.